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Those paper receipts you often collect after visiting the ATM, grocery store, shopping mall, or gas station may be harming your precious health. Researchers have discovered that continuous handling of receipts printed on thermal paper is linked to higher levels of BPA detected in urine. Their work appears in the most recent issue of JAMA.

Bisphenol A or BPA is a chemical compound that is commonly used to make plastic products, including the many bottles containing water and other beverages. BPA-based plastics have been in commercial use since 1957 and in the U.S., exposure to BPA is widespread. The Centers for Disease Control and Prevention found detectable levels of BPA in 93 percent of over 2,500 urine samples collected from people ages 6 and older. Yet, the Food and Drug Administration (FDA) supports the safety of BPA in currently approved practices. "FDA has performed extensive research and reviewed hundreds of studies about BPA’s safety," reads the agency website. "We reassure consumers that current approved uses of BPA in food containers and packaging are safe. Additional research is underway to enhance our understanding of BPA."

That said, BPA continues to be a controversial topic, in which scientific opinions conflict. One recent study, for instance, found overly high exposure caused malformation in rat babies leading the researchers to suggest it may also cause health problems in humans; another study conducted in mice and other animals found embryo exposure to be problematic. So though many people are aware that high exposure to BPA may be destructive to their health, what few people know is that BPA is also used to make thermal receipt paper, which they may be handling on a near daily basis.

To conduct a study of exposure to BPA in receipt paper, Dr. Shelley Ehrlich of Cincinnati Children's Hospital Medical Center and her colleagues recruited 24 volunteers who provided urine samples before and after handling (with or without gloves) receipts printed on thermal paper for two hours continuously. Thermal paper has a coating that is necessary to the process of printing, but when handled, readily transfers to the skin. First, the participants printed and handled receipts continuously for two hours without gloves. Second, after a washout period of at least seven days, participants repeated the handling of receipts, but this time they wore nitrile gloves. Importantly, all the participants provided a spot urine sample immediately before handling the receipts and four hours later. Additional urine samples were collected after eight, 12, and 24 hours.

What did the researchers discover? They detected BPA in 83 percent of the urine samples at the beginning of the study and in 100 percent of the samples after handling receipts without gloves. Urinary BPA concentrations increased after handling receipts without gloves, but did not significantly change among the participants who used gloves.

When ingested, BPA has been shown to be an endocrine disruptor and is linked to various negative health consequences. “Exposure to BPA is primarily through dietary ingestion, including consumption of canned foods,” wrote the authors. “Human exposure to bisphenol A (BPA) has been associated with adverse health outcomes, including reproductive function in adults and neurodevelopment in children exposed perinatally.”

The authors believe their work is particularly relevant to people who are occupationally exposed to thermal paper, “such as cashiers, who handle receipts 40 or more hours per week.” According to the most recent Bureau of Labor statistics, cashiers held about 3.3 million jobs and about half of all cashiers were 24 years old or younger. "A larger study is needed to confirm our findings and evaluate the clinical implications,” the authors wrote.